Problem: Each person marked the table with an X on the day(s) he/she would not be able to attend a meeting. On which day can the most people attend a meeting?

\begin{tabular}{|l|c|c|c|c|c|}
\multicolumn{6}{c}{}\\\hline
&Mon&Tues&Wed&Thurs&Fri\\\hline
Anna&X&&X&&\\\hline
Bill&&X&&X&X\\\hline
Carl&X&X&&X&X\\\hline
\end{tabular}
Answer: On each day but Wednesday, only one person can attend a meeting. On Wednesday, two people can. Thus, the day on which the most people can attend a meeting is $\boxed{\text{Wednesday}}.$